Aerosoft Da-20-100 Katana engine management?

It should be pretty easy but I have hard time to mantain good cruise speed - low consuption ratio. On takeoff and climb I keep prop lever on max, and since v/s is about 700ft/m, it burns too much fule up to cruise level. Yesterday I did a test, about 30nm circle around home airport, started at 46% fuel, ended the flight at 37%! 60% of the flight I was on 6000ft short cruise, trying to keep 105kts, but I could keep it only on full power and 75-80% prop. Katana doesn't have mixture control (which I find that quite unusual), and what is more strange, aircraft reacts to my mixture level changes on my Saitek quadrant! I can clearly hear the change in rpm when fiddling with mixture level. Apparently developer forgot to remove mixture feature from the aircraft? Also I didn't knew that Katana has carb hear lever, I don't understand german text above the knobs and levers.

So, if the aircraft consumed 9% of fuel on 30nm trip, how in the world I can fly for 800-900nm, as the specification clearly says?

Appart from my "hungry plane" problem, this plane is a joy to fly, nice little change after A2A.

So what's are the usual cruise settings? I guess it's 70-80%, and prop from 1800-2200rpm? What is the usual cruise speed with that settings?

Cheers!